Source : Webster's Revised Unabridged Dictionary (1913)

Usury \U"su*ry\, n. [OE. usurie, usure, F. usure, L. usura use,
   usury, interest, fr. uti, p. p. usus, to use. See {Use}, v.
   t.]
   1. A premium or increase paid, or stipulated to be paid, for
      a loan, as of money; interest. [Obs. or Archaic]

            Thou shalt not lend upon usury to thy brother; usury
            of money, usury of victuals, usury of anything that
            is lent upon usury.                   --Deut. xxiii.
                                                  19.

            Thou oughtest therefore to have put my money to the
            exchanges, and then at my coming I should have
            received mine own with usury.         --Matt. xxv.
                                                  27.

            What he borrows from the ancients, he repays with
            usury of ??is own.                    --Dryden.

   2. The practice of taking interest. [Obs.]

            Usury . . . bringeth the treasure of a realm or
            state into a few ??nds.               --Bacon.

   3. (Law) Interest in excess of a legal rate charged to a
      borrower for the use of money.

   Note: The practice of requiring in repayment of money lent
         anything more than the amount lent, was formerly
         thought to be a great moral wrong, and the greater, the
         more was taken. Now it is not deemed more wrong to take
         pay for the use of money than for the use of a house,
         or a horse, or any other property. But the lingering
         influence of the former opinion, together with the fact
         that the nature of money makes it easier for the lender
         to oppress the borrower, has caused nearly all
         Christian nations to fix by law the rate of
         compensation for the use of money. Of late years,
         however, the opinion that money should be borrowed and
         repaid, or bought and sold, upon whatever terms the
         parties should agree to, like any other property, has
         gained ground everywhere. --Am. Cyc.

Source : WordNet®

usury
     n 1: an exorbitant or unlawful rate of interest [syn: {vigorish}]
     2: the act of lending money at an exorbitant rate of interest